1. Technical Field of the Invention
This invention pertains generally to an analyte test strip assembly for use in diagnostic testing for an analyte concentration. More specifically, the invention pertains to an integrated needle and test strip assembly, which may include a catheter, conduit, or aspirating chamber, and which may collect a sample of blood or interstitial fluid cutaneously or subcutaneously from a patient and, in conjunction with an analyte meter, measure an analyte concentration.
2. Background of the Invention
Electronic testing systems are commonly used to measure or identify one or more analytes in a sample. Such testing systems can be used to evaluate medical samples for diagnostic purposes and to test various non-medical samples. For example, medical diagnostic meters can provide information regarding presence, amount, or concentration of various analytes in human or animal body fluids. In addition, diagnostic test meters can be used to monitor analytes or chemical parameters in non-medical samples such as water, soil, sewage, sand, air, or any other suitable sample.
Diagnostic testing systems typically include both a test medium, such as a diagnostic test strip, and a test meter configured for use with the test medium. Suitable test media may include a combination of electrical, chemical, and/or optical components configured to provide a response indicative of the presence or concentration of an analyte to be measured. For example, some glucose test strips include electrochemical components, such as glucose specific enzymes, buffers, and one or more electrodes. The glucose specific enzymes may cause a reaction between glucose in a sample and various chemicals on a test medium, thereby producing an electrical signal that can be measured with the one or more electrodes. The test meter can then convert the electrical signal into a glucose test result.
Diagnostic testing systems have improved significantly in recent years. For example, test meters have become smaller and faster, and the amount of blood or other fluid needed to obtain accurate test results has decreased. However, although these improvements have made testing more convenient for patients, current systems have some drawbacks. For example, current systems and devices for monitoring blood glucose levels in diabetic patients require three separate devices; a lancet, a blood glucose meter, and test strips. The need to carry these three items can be inconvenient and cumbersome. In addition, carrying more components makes it easier to misplace or lose a component. Further, the current systems frequently employ lancets which can be reused. Reusing the same lancet is less sanitary than using a new, disposable lancet each time and can cause the lancet to become dull over time, leading to more pain for the patient upon use.
The pain associated with the use of a lancet is a constant concern for diabetic patients. Current lancets use a myriad of different engagement devices to create the wound. The most common method involves the use of a spring loaded lancet strike to breach the patient's skin and thereby insert the lancet. This unpleasant method has substantial drawbacks such as lancet needle movement, vibration or misapplication of force by the lancet triggering device. The overall objective of the lancet is to cause a wound that will produce blood on the surface of the skin.
Since the advent of these point of care testing systems in the 1970s (“Glucose sensors: a review of current and emerging technology,” N. S. Oliver, et. al., Diabetic Medicine, 26:197-210, 2009; incorporated herein by reference), a non-invasive method of determining an analyte concentration such as glucose has been intensively sought and researched. To date the search has not yet resulted in a United States FDA approved device of acceptable accuracy (N. S. Oliver, et. al.). Other analytes of greater concentration have been shown to be amenable to noninvasive testing, for example, carboxyhemoglobin, as described in U.S. Pat. Nos. 5,692,503 and 6,393,310 B1, and hemoglobin, as described in U.S. Pat. No. 5,377,674 for total hemoglobin, all to this inventor. Devices are now being sold that measure these analytes noninvasively.
However, the search for a noninvasive method for the measurement of other analytes such as, for example, glucose has proven more elusive. As such, while the current methods and systems facilitate the self-monitoring of analyte concentrations in blood or bodily fluid, there is need for additional features and improvements, including systems with fewer components, less painful blood or interstitial fluid collection, more precise fluid collection methods for elderly or less dexterous patients, and less cumbersome and cleaner fluid collection methods. The present invention overcomes many of the shortcomings of the prior art of lancets and test strips.